The question is not whether the Landlord is responsible for the damage or the missing items but whether you could prove to a small claims judge that the Landlord is responsible. You should try to document whatever you can with pictures or letters to the Landlord with the purpose of memorializing events that transpired (or that you think transpired). Also try to obtain witnesses who may be able to help you in a small claims action by testifying against the Landlord. If individuals are not able to testify in a small claims action on your behalf, you should obtain sworn declarations which support your case.
This answer should not be considered legal advice and does not create an attorney/client relationship. You should hire an attorney in NJ to help you with your issue.